Rostroconchia

Conocardium sp., from here.

Belongs within: Mollusca.
Contains: Scaphopoda.

The Rostroconchia are a group of molluscs known from the Cambrian to Late Permian. They possess a pseudobivalved shell, with the valves joined by an anterior partition called the pegma that in life also provided the attachment site for the pedal retractor muscles; a posterior pegma may also be present (Prothero 1998). Some authors regard the rostroconchs as ancestral to the modern Scaphopoda; others place them closer to the bivalves (suggestions that they may be ancestral to both are inconsistent with the tendency for most recent phylogenetic studies to not place the two lineages as closely related).

<==Rostroconchia
    |  i. s.: Heraultipegma P98
    |--Ribeirioida P04
    |    |--Ribeiria [Ribeiridae] P04
    |    |    |--R. apusoides Schubert & Waagen 1903 HMY02
    |    |    `--R. junior Runnegar 1996 P04
    |    `--Pinnocaris Etheridge 1878 P04
    |         |--P. lapworthi Etheridge 1878 P04
    |         `--P. wellsi PR79
    `--+--+--Scaphopoda P04
       |  `--+--Jinonicella Pokorny 1978 [Jinonicellidae] PR79
       |     `--Janospira Fortey & Whittaker 1976 PR79
       |          `--J. nodus Fortey & Whittaker 1976 PR79
       `--Conocardioida [Conocardioidea] HP03
            |  i. s.: Hippocardia Brown 1843 P04, HMY02
            |           |--H. alborza HMY02
            |           |--H. bohemica (Barrande 1881) HMY02
            |           |--H. cunea (Conrad 1840) HMY02
            |           `--H. kermani Hoare & Aghababalu 2001 HMY02
            |--Pseudobigaleaidae HP03
            |    |--Pseudobigalea Hoare et al. 1982 HMY02
            |    |    `--*P. crista Hoare, Mapes & Brown 1982 (see below for synonymy) HMY02
            |    |--Exalloschema Hoare, Mapes & Yancey 2002 HMY02
            |    |    `--*E. batilia (Hoare, Mapes & Brown 1982) [=Hippocardia batilia] HMY02
            |    |--Minycardita Hoare & Plas 2003 HP03
            |    |    `--*M. sectilis Hoare & Plas 2003 HP03
            |    |--Baiosoma Hoare, Mapes & Yancey 2002 HP03
            |    |    |--*B. pala (Hoare, Steinker & Mapes 1988) [=Hippocardia pala] HMY02
            |    |    `--B. cucullata (Hoare et al. 1988) [=Hippocardia cucullata] HMY02
            |    `--Hadropipetta Hoare, Mapes & Yancey 2002 HP03
            |         |--*H. ancora (Hoare, Steinker & Mapes 1988) [=Hippocardia ancora] HMY02
            |         `--H. nevadaensis Hoare & Plas 2003 HP03
            |--Bransoniidae HMY02
            |    |--Pseudoconocardium Zavodowsky 1960 HMY02
            |    |    `--*P. licharewi HMY02
            |    |--Bransonia Pojeta & Runnegar 1976 HMY02
            |    |    |--*B. wilsoni Pojeta & Runnegar 1976 HP03
            |    |    `--B. robustum (Fletcher 1943) [=Conocardium robustum] HMY02
            |    `--Apotocardium Hoare, Mapes & Yancey 2002 HMY02
            |         |--*A. lanterna (Branson 1965) [=Conocardium lanterna, Pseudoconocardium lanterna] HMY02
            |         |--A. cordatum (Hoare et al. 1982) [=Pseudoconocardium cordatum] HMY02
            |         |--A. obliquum (Meek & Worthen 1875) [=Conocardium obliquum] HMY02
            |         |--A. plautum Hoare, Mapes & Yancey 2002 HMY02
            |         |--A. polymitarium (Hoare et al. 1982) [=Pseudoconocardium polymitarium] HMY02
            |         `--A. snideri (Morgan 1924) [=Conocardium snideri, Pseudoconocardium snideri] HMY02
            `--Conocardiidae HMY02
                 |--Oxyprora Hoare, Mapes & Yancey 2002 HMY02
                 |    |--*O. parrishi (Worthen 1890) [=Conocardium parrishi] HMY02
                 |    |--O. missouriensis (Girty 1915) (see below for synonymy) HMY02
                 |    `--O. oklahomaense (Beede 1902) [=Conocardium oklahomaense] HP03
                 |--Arceodomus Pojeta & Runnegar 1976 P04
                 |    |--*A. glabrata (Easton 1962) [=Conocardium glabratum] HMY02
                 |    |--A. angusta Hoare, Mapes & Yancey 2002 HMY02
                 |    |--A. langenheimi (Wilson 1970) HMY02
                 |    |--A. prolata Hoare & Mapes 1990 HMY02
                 |    `--A. sphairikos Hanger et al. 2002 HMY02
                 `--Conocardium Bronn 1835 P04
                      |--C. abscissum Fletcher 1943 F71
                      |--C. acadianum Dawson 1891 HMY02
                      |--C. australe (M’Coy 1847) [=Pleurorhynchus australis] F71
                      |--C. davidis Dun 1907 F71
                      |--C. laseroni Fletcher 1943 F71
                      |--C. mundulum Fletcher 1943 F71
                      |--C. nicholasensis Price 1921 (n. d.) HMY02
                      |--C. semiplenum White 1877 W77
                      |--C. sowerbyi F71
                      |--C. trigonale W77
                      `--C. truncatum Fletcher 1943 F71

Oxyprora missouriensis (Girty 1915) [=Conocardium missouriensis, Pseudoconocardium missouriensis] HMY02

Pseudobigalea crista Hoare, Mapes & Brown 1982 [=Pseudoconocardium parrishi (Worthen) in Hoare, Sturgeon & Kindt 1978 non Conocardium parrishi Worthen 1890] HMY02

*Type species of generic name indicated

REFERENCES

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1-167.

[HMY02] Hoare, R. D., R. H. Mapes & T. E. Yancey. 2002. Structure, taxonomy, and epifauna of Pennsylvanian rostroconchs (Mollusca). Journal of Paleontology 76 (Suppl.): 1-30.

[HP03] Hoare, R. D., & L. P. Plas Jr. 2003. Permian rostroconchs (Mollusca) from Nevada. Journal of Paleontology 77 (5): 873-875.

[P04] Peel, J. S. 2004. Pinnocaris and the origin of scaphopods. Acta Palaeontologica Polonica 49 (4): 543-550.

[PR79] Pojeta, J., Jr., & B. Runnegar. 1979. Rhytiodentalium kentuckyensis, a new genus and new species of Ordovician scaphopod, and the early history of scaphopod mollusks. Journal of Paleontology 53 (3): 530-541.

[P98] Prothero, D. R. 1998. Bringing Fossils to Life: An introduction to paleobiology. WCB McGraw-Hill: Boston.

[W77] White, C. A. 1877. Report upon the invertebrate fossils collected in portions of Nevada, Utah, Colorado, New Mexico, and Arizona, by parties of the expeditions of 1871, 1872, 1873, and 1874. U.S. Geographical Surveys West of the One Hundredth Meridian 4 (1): 1-219, pls 211-221.